Process of drying lumber



F. K.v FISH, JR. PROCESS 0F DRYING LUMBER.

APPLICATION FILED DEC. Il, I9I9.

Patented J an. 20, 1920.

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F. K. FISH, 1R.

PROCESS OF DHYING LUMBEH.

APPLICATION FILED DEC. I7, I9I9.

1,3 28,66% Patented Jan. 20, 1920.

S SHEETS-SHEET 2.

F. K. FISH, III. PROCESS 0F DIIYING LUMBER. APPLICATION FILED Dsc. II. Ism.

`1328,662.` .Patented Jan. 20, 1920.

3 SHEETS-SHEET 3.

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PRCESS F DRYNG LUMIERE.

.ww-modem Speccetlon ci' Letters Ietent.

Patented den, Lilli, i920?.

Application med number i?, wie, termi ne.

To el@ whom t may consom.'

lie it known that l Fniinnnioit l. Fien e speclicetion.

The present invention is based upon e. proper recognition of the physiezil cherecteristics ot wood structure, constituency of its fluid content, and the possibility of coi'iverting` into-en agency for preservatiom rtein of its contained elements, which, under naturel conditions, would form the basis o" its deterioration or destruction.

Stiuctureliy, Wood coneiets of e skeleton of cellulose intermingled with other organic substances, collectively designated ce lignin, togethei1 with e ininor proportion of ininerel metter or ash. Ligniiu While not fully understood chemically, is closel Y allied to the cellulose element of the Woo end since it forms a part of the permanent structure of the Wood, it moy, for purposes of the present invention, he 'regarded identical with the cellulose.

To utilize the naturel bases of resin., acetic acid. and tennic acid, existing .in Wood, as reservetives of the Wood, it is necessary t at they be dislodged from their cellular connement, seperated from their aqueous solvent or vehicle, converted. by oxidation end properly distributed through or deposited upon the collider and the fibrous structure of the Wood.

The release and conversion of the@ properties, especially 'the most important 'o them, namely, the volatile oils which, when. oxidized, form resin, is accomplished, eccording to my invention, by first sweatin the Wood; then submitting the green woo to e beth of free steam under pressure; Ypreferably of about twenty pounds, for e sufficient period of time, to thoroughly open up the pores of the Wood, dissolve its gummy sep mettere that line its cellular tissues and put it into good physical condition to readily give up its aqueous content, Without 'l Ehysicel deterioration of'- checking` or other the wood piece. T is steam bath causes. the

aqueous content of the Wood to evaporate, without taking with it, the voluesof the sap, such as resin oi` resin-producing oil.

the chemicol y Next. the wood issuhjected to artificiel heet,

Iwhich consists in maintaining around it, en. etxnosphei'e et e temperature euiicient to reuse continuous evaporation omoistuce throughout the hiess oi wood; nelly' the wood is dried in ai moderotely heoted, atmosphere.

And all theee` conditions ere attained Without checking, warping., cese hardening or other dctei'io-i'tion oi" the physical einen :icteristics oi' the vvood.

By 'wey of teeclliing the invention more in: detail, one approved niethod oi: practising the some will loe described with reference to the accompanying drawings, in which Figure l is o vertical longitudinali section of :t stcrilizer, suitable for carrying; out the tiret step of the process. y

' Fig. 2 ie :i section teiten on line 5-5 llig. 3 is o, vertical longitudinnl section. of en equnlizing cheminer.

Fig. l is e section on the line owe, Fig., 3'.

Fig. 5 is o, pien View oi the 'verious conn miners incident the 1 defying ont of the process showing other ineens ci intercominunicetion.

l represents e :sterilizer construction elzitohle for conteining stento onder preesure. lt is preferebly provided with e presser plete 2 with edyusting screwe 3, through means which the charge et lont treated. lt is eho provided with heating* coils fl, loy which, the temperature of the atmosphere or steam within the eterilizcr muy be heated tojtlie desired degree; oud with coils 5 Which-tney he perforated oi the purpose of suppl* lng free stoom within the sterilieer when deeieed. l2 represents trocito to receive the oei* or txuci: upon which the bei may be kept 'l-nder pressure While heilig lumber' ie loededl'oi introduction into the stemlmer. y

Referrin to Figs. 3 und i235 ie'presents the equelizin cheinber whicli ie preferably piotiided Wit e pressure device il, 3, sinn ler 1n principle to that employed in the (lll sterilizer, with heeting pipes i4 preiie'iooly loaded et the bottom, enen" inlet or domper 16, end an eir outlet or dem er 17. This; e nalizing chemisier is fort` et' provided with tracks 15 for convenient introduction of the charge of lumber, and its Welle one, preferably constructed eo es to lieve e high coelicient of heet insulation for the celte of economy in operation.

Referring to Fig. 5, 18represents a sweating chamber adapted to hold one or more truck loads ot' lumber; 19 is a sterilizer; 20 a track which passes through sweat cham ber 18 and sterilizer 19 for the convenient introduction thereinto of a load of lumber; 21 is a transt'er platform having insulated walls adapted to 'completely surround the ioad of lumber when withdrawn from sterf In carrying out the processl with the apparatus above described, a suitable charge of lumber loaded on a truck, is introduced into the sweating chamber 18 for a period of time and is then transferred into sterilizer 1, which is then hermetically closed and steam supplied through the spray pipes To create the next step, the sterllizer 1 is opened and the ioad of lumber is removed therefrom and ltransferred as rapidly as possible to the equalizing chamber 13, the load being` covered to minimize the loss ot' heat during the transfer. Sterilizer 1 is now ready to repeat the second step of the process While the equalizing step is being l carried on in the equalizing chamber 13, said chamber already heated is closed upon the load of lumber, the heating pipes 14 are operated suiiiciently to keep up a temperature favorable/to continuous evaporation of mo1sture from the lumber; and the damper 16 at the base and 17 in the stack are opened periodically to create a draft or current of 'air for carrying oil' the moisture as' it accumulates or may be kept open continu- Qusly for this purpose. After the desired amount of moisture has been withdrawn from the Wood and the resins have thoroughly permeated the cellular structure thereof, the lumber is transferred into cooling chamber 26 upon track 25 in which chamber there has been previously created a {moderately heated, moist atmosphere.

QFrom the foregoing", it will be seenA that the first essential condition tobe' produced is the thorough softening and opening up ofl the Wood structure and the dissolving of its gummy sap matters and freeing them from their confinement, which condition is obtained by subjecting the wood to a steam bath, or moist atmosphere under pressure; the final step brings about complete drying under conditions that evaporate the remaininv moisture at atmospheric pressure in a su iciently gradual manner to avoid taking the resin away from the wood structure.

I claim l 1. The process of drying wood, which consists in sweating the wood; then creating around it a body of steam under pressure; then subjecting the wood to dry heat; inally drying in a moderately heated, moist atmosphere.

2. The process ot' drying wood, which consists in subject-ing the wood to a moderately heated, moist atmosphere; then surrounding it with a body of steam under pressure; then subjecting it to dry heat: finally subjecting it to a moderately heated, moist atmosphere.y the wood being kept under mechanical pressure during these steps.

3. The process of drying wood, which consists in placing the wood in a sweat chamber, creating in said chamber a moderately heated.I moist atmosphere; then placing the wood in a sterilizer and producing therein a body of steam under pressurer then placing the wood in an equalizing chamber and subjecting it to dry heat finally placing it in a cooling chamber and creating therein a moderately heated', moist atmosphere.

i. The process of dryingmwood, which consists in sweating the wood; then placing the wood in a sterilizer and ini'ecting therein steam under pressure; then lsubjecting the wood to dry heat; finally drying in the presence oli a moderately heated, moist ati mosphere.

5. The process of dryingwood, which consists in irst sweating the Wood; then placing it in a sterilizer and producing around it a body of steam under pressure to open up its pores and soften :its structure; then subjecting it to dry heat :then creating around the Wood a body of moderately heated, moist atmosphere unt-il the internal temperature of the Wood and the surround.- ing atmosphere have been harmonized.

In testimony whereof I my signature.

FREDERICK K. FISH, Je. 

